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IL-25 Induced ROS-Mediated M2 Macrophage Polarization via AMPK-Associated Mitophagy
Mei-Lan Tsai1,2, Yi-Giien Tsai3,4,5, Yu-Chih Lin6,7
1Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
Abstract:
Interleukin (IL)-25 is a cytokine released by airway epithelial cells responding to pathogens. Excessive production of reactive oxygen species (ROS) leads to airway inflammation and remodeling in asthma. Mitochondria are the major source of ROS. After stress, defective mitochondria often undergo selective degradation, known as mitophagy. In this study, we examined the effects of IL-25 on ROS production and mitophagy and investigated the underlying mechanisms. The human monocyte cell line was pretreated with IL-25 at different time points. ROS production was measured by flow cytometry. The involvement of mitochondrial activity in the effects of IL-25 on ROS production and subsequent mitophagy was evaluated by enzyme-linked immunosorbent assay, Western blotting, and confocal microscopy. IL-25 stimulation alone induced ROS production and was suppressed by N-acetylcysteine, vitamin C, antimycin A, and MitoTEMPO. The activity of mitochondrial complex I and complex II/III and the levels of p-AMPK and the mitophagy-related proteins were increased by IL-25 stimulation. The CCL-22 secretion was increased by IL-25 stimulation and suppressed by mitophagy inhibitor treatment and PINK1 knockdown. The Th2-like cytokine IL-25 can induce ROS production, increase mitochondrial respiratory chain complex activity, subsequently activate AMPK, and induce mitophagy to stimulate M2 macrophage polarization in monocytes.
Insights
Interleukin-25 (IL-25) induces reactive oxygen species (ROS) and activates mitophagy in monocytes. This process enhances mitochondrial activity and promotes M2 macrophage polarization, potentially impacting airway inflammation.
Area of Science:
- Immunology
- Cell Biology
- Mitochondrial Biology
Background:
- Interleukin-25 (IL-25) is a cytokine involved in airway responses to pathogens.
- Excessive reactive oxygen species (ROS) production contributes to airway inflammation and remodeling in asthma.
- Mitochondria are a primary source of ROS, and their selective degradation via mitophagy is a cellular stress response.
Purpose of the Study:
- To investigate the effects of IL-25 on ROS production and mitophagy in human monocytes.
- To elucidate the underlying molecular mechanisms connecting IL-25, ROS, and mitophagy.
Main Methods:
- Human monocyte cell lines were treated with IL-25.
- ROS production was quantified using flow cytometry.
- Mitochondrial activity, mitophagy markers, and cytokine secretion were assessed via ELISA, Western blotting, and confocal microscopy.
Main Results:
- IL-25 stimulation increased ROS production, which was mitigated by antioxidants and mitochondrial inhibitors.
- IL-25 enhanced mitochondrial respiratory chain complex activity and increased levels of p-AMPK and mitophagy-related proteins.
- CCL-22 secretion was elevated by IL-25 and reduced by mitophagy inhibition and PINK1 knockdown.
Conclusions:
- The Th2-like cytokine IL-25 induces ROS production and activates mitophagy through increased mitochondrial activity and AMPK signaling in monocytes.
- This IL-25-mediated pathway promotes M2 macrophage polarization, suggesting a role in inflammatory responses.
